Off topic:HOW EDIT VCF FILE COLUMNS

Question

[misbahabas]

I want to change position column in vcf files. Please tell me any script or tool which solve the following issues. I am new in programming

If I have a vcf file like this

pos ref alt
1 C G
2 A T
3 C G
4 T C
5 G C
6 T A
7 T G
8 C T
9 A C
10 C A

Now I want to add some value in vcf positions values untill ending position come like add 10 into position values until 15 then move next value 18 and add until 25 come

10-15
18-25
40-50

I want output like this

pos ref alt
11 C G
12 A T
13 C G
14 T C
15 G C (when 15 come it stops addition and move next value)
24 T A
25 T G (second ending position come now move next)
48 C T
49 A C
50 C A

Please give me any idea about it

Thanks